title: Nitric oxide synthase-2 modulates chemokine production by Trypanosoma cruzi-infected cardiac myocytes.
abstract: An intense inflammatory process is associated with Trypanosoma cruzi infection. We investigated the mediators that trigger leukocyte activation and migration to the heart of infected mice. It is known that nitric oxide (NO) modulates the inflammatory response. During T. cruzi infection, increased concentrations of NO are produced by cardiac myocytes (CMs) in response to IFN-gamma and TNF. Here, we investigated whether NO, IFN-gamma and TNF regulate chemokine production by T. cruzi-infected CMs. In addition, we examined the effects of the NOS2 deficiency on chemokine expression both in cultured CMs and in hearts obtained from infected mice. After infection of cultured WT CMs with T. cruzi, the addition of IFN-gamma and TNF increased both mRNA and protein levels of the chemokines CXCL1, CXCL2, CCL2, CCL3, CCL4 and CCL5. Interestingly, T. cruzi-infected NOS2-deficient CMs produced significantly higher levels of CCL2, CCL4, CCL5 and CXL2 in the presence of IFN-gamma and TNF. Infection of NOS2-null mice resulted in a significant increase in the expression of both chemokine mRNA and protein levels in the heart of, compared with hearts obtained from, infected WT mice. Our data indicate that NOS2 is a potent modulator of chemokine expression which is critical to triggering the generation of the inflammatory infiltrate in the heart during T. cruzi infection.
authors.affiliation: Departments of Biochemistry and Immunology and Pathology, School of Medicine of Ribeirão Preto-USP, Ribeirão Preto, SP, Brazil. machadofs@icb.ufmg.br
authors.forename: Fabiana S
authors.initials: FS
authors.lastname: Machado
authors.forename: Janeusa T
authors.initials: JT
authors.lastname: Souto
authors.forename: Marcos A
authors.initials: MA
authors.lastname: Rossi
authors.forename: Lisia
authors.initials: L
authors.lastname: Esper
authors.forename: Herbert B
authors.initials: HB
authors.lastname: Tanowitz
authors.forename: Julio
authors.initials: J
authors.lastname: Aliberti
authors.forename: João S
authors.initials: JS
authors.lastname: Silva
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D018925:Chemokines / Q000096:biosynthesis*; D020869:Gene Expression Profiling; D007371:Interferon-gamma / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D009206:Myocardium / Q000473:pathology; D032383:Myocytes, Cardiac / Q000276:immunology* / Q000469:parasitology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000172:deficiency / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000382:microbiology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D018925:Chemokines; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma; D052247:Nitric Oxide Synthase Type II